Preheat oven to 375 degrees F/190 degrees C/Gas Mark 5. Oil and flour a 9 in by 5 in by 3 in pan. Metal is best. Glass will probably work well, too.

Place warm milk/water into a small bowl. Whisk in 1 tablespoon of sugar until dissolved. Whisk in yeast until dissolved. Set aside to proof (get foamy and verify the yeast is working).

In a medium bowl, mix together the flour, xanthan gum, baking powder, salt, and the remaing 3 tablespoons sugar.

In the bowl of a stand mixer fitted with the paddle attachment, place eggs, olive oil, and vinegar. Beat for a few seconds to combine. Add the yeast mixture. Beat a few seconds more to combine. Add the flour mixture. Beat on medium high for 3 minutes.

Scrape mixture into your prepared loaf pan (it will be a thick batter) and smooth the top. Place in a warm, draft-free spot to rise until about half again its size in bulk (not quite double)–about 30-40 minutes at sea level. Basically, you want it to look a bit puffed up. I usually do this on top of the stove while the oven is preheating–this allows the oven’s warmth to help the bread rise. Watch it–don’t let it rise too much. It should only rise to the top or a bit above the top of the pan.

Bake at 375 degrees for 20 minutes. If the top of the bread is getting too brown, place a tent of foil over it. Bake for another 10 minutes for a total of 30 minutes.

Remove from oven and let cool in pan for 5 minutes. Then carefully turn out onto rack to cool completely.